Using a matched cohort design, a sample of adolescent hypertensives and normotensives with and without a familial predisposition to hypertension will be selected from the 8th grade population of the Dallas Independent School District. The objective of the present proposal is to study differential autonomic responses of Black, White and Mexican-American hypertensive and normotensive adolescents to various physical and psychological stimuli. Cardiovascular and sweat gland response patterning will be measured in response to simple and complex stimuli such as audio tones, white noise, aversive slides, cold pressor test, aversive movie, classical conditioning. Behavioral differences along the line of Type A and Type B personality patterns will also be investigated.